The report was so "seismic" -- Daniel Patrick Moynihan's word -- that Lyndon Johnson's administration released it on the Fourth of July weekend, 1966, hoping it would not be noticed. But the Coleman report did disturb various dogmatic slumbers and vested interests. And 50 years on, it is pertinent to today's political debates about class and social mobility. So, let us now praise an insufficiently famous man, sociologist James Coleman, author of the study "Equality of Educational Opportunity."

In 1966, postwar liberalism's confidence reached its apogee. From 1938, when the electorate rebuked Franklin Roosevelt for his plan to "pack" the Supreme Court, through 1964, congressional Republicans and conservative Democrats prevented a liberal legislating majority. But Johnson's 44-state victory that year gave Democrats 68 Senate seats and a majority of 155 in the House. Effortless and uninterrupted prosperity seemed assured as the economy grew in 1965 and 1966 by 10.7 percent and 7.99 percent, respectively. So, a gusher of tax revenues coincided with liberalism's pent-up demand for large projects. It hoped to meld two American traits -- egalitarian aspirations and faith in education's transformative power.

The consensus then was that the best predictor of a school's performance was the amount of money spent on it: Increase financial inputs and cognitive outputs would increase proportionately. As the postwar baby boom moved through public schools like a pig through a python, almost everything improved -- school buildings, teachers' salaries, class sizes, per pupil expenditures -- except outcomes measured by standardized tests.

Enter Coleman, and the colleagues he directed, to puncture complacency with the dagger of evidence -- data from more than 3,000 schools and 600,000 primary and secondary school students. His report vindicated the axiom that social science cannot tell us what to do, it can tell us the results of what we are doing. He found that the best predictor of a school's outcomes is the quality of the children's families. And students' achievements are influenced by the social capital (habits, mores, educational ambitions) their classmates bring to school:

"One implication stands out above all: That schools bring little influence to bear on a child's achievement that is independent of his background and general social context; and that this very lack of an independent effect means that the inequalities imposed on children by their home, neighborhood, and peer environment are carried along to become the inequalities with which they confront adult life at the end of school."

Coleman's report came exactly one year after -- and as an explosive coda to -- what is known as the Moynihan Report, which was leaked in July 1965. Moynihan, then a 37-year-old social scientist in Johnson's Labor Department, presented in "The Negro Family: The Case for National Action" what then counted as shocking news: 23.6 percent of African-American births were to unmarried women.

Today 71 percent are. Almost 47 percent of all first births are to unmarried women, and a majority of all mothers under 30 are not living with the fathers of their children.

The causes of family disintegration remain unclear, but 51 years ago Moynihan and then Coleman foresaw the consequences. Moynihan said the "tangle" of pathologies associated with the absence of fathers produces a continually renewed cohort of inadequately socialized adolescent males. Socializing them is society's urgent business if it is to avoid chaotic neighborhoods and schools where maintaining discipline displaces teaching. Coleman documented how schools are reflections of, rather than cures for, the failure of families to function as the primary transmitters of social capital.

The extraordinary synergy between Moynihan and Coleman was serendipitous. Today, their baton of brave and useful sociology has passed to Charles Murray of the American Enterprise Institute. His "Losing Ground" (1984) was an autopsy of 1960s aspirations. His "Coming Apart" (2012) explores the social consequences -- we are wallowing in the political consequences -- of a bifurcated society in which many do very well while many others are unable to reach even the lowest rungs on the ladder of upward mobility.

Coleman's evidence that cultural rather than financial variables matter most was not welcomed by education bureaucracies and unions. Similarly, we now have more than half a century of awkward, and often ignored, evidence about the mostly small and evanescent effects of early childhood education. Today's Democratic Party fancies itself "the party of science"; Barack Obama pledged, in his first inaugural address, to "restore science to its rightful place." Social science, however, is respected by Democrats only when it validates policies congenial to the interests of favored factions.